This invention relates generally to well installations, and more particularly concerns the use of well equipment constructed of non-metallic materials.
In the past, it has been thought necessary for many reasons including strength and durability to employ well sucker rod, casing and tubing consisting of steel, and the design of well installations has been predicated on the use of such material. However, employment of steel introduces many problems among which are the large loads that must be handled, included lifting and lowering of extremely heavy sucker rod lengths in deep wells (over 10,000 feet) which limits well depth and necessitates use of very large and heavy surface lifting equipment; the problems of rust and corrosion which is extremely critical in offshore installation; and the problems of magnetism induced in installed tubing, casing and sucker rods, which leads to lateral attraction of these elements resulting in excess friction and wear. For example, 15,000 feet of steel sucker rod will commonly impose a load of over 40,000 pounds on the surface lifting equipment, whereas the corresponding fluid column weight will be around 8,000 pounds. If the sucker rod weight could be substantially reduced, the capacity size and cost of the lifting equipment could be markedly lowered.